1. Field of the Invention
The present invention relates to a method of computing the overall mechanical material constant, as the mechanical characteristic, of a composite material which includes material components in a matrix phase, each of the mechanical material constants of the material components and the matrix phase being known. Additionally, the present invention relates to a method of computing the volume fraction of a material component in a composite material which includes material components in a matrix phase, each of the mechanical material constants of the material components and the matrix phase being known. Furthermore, the present invention relates to a recording medium storing a program for a computer to execute the aforementioned methods.
2. Description of the Related Arts
Conventionally, a variety of attempts have been actively employed for accurately estimating the mechanical characteristic of a composite material in which predetermined material components are dispersed in a matrix phase. The estimation intends to efficiently identify a variety of factors using a computer for tailoring the composite material to have a desired characteristic, instead of finding them by conducting an actual experiment. For example, the factors may include identification of the mechanical characteristics of the material components in the composite material and the volume fractions of the material components. As a result, it is possible to design a mixture of components with desired characteristics in an early stage.
Under the circumstance, JP-A-2007-122242 discloses a method for analyzing a macro-structure which consists of multiple minute elements in which a micro-structure that has a three-dimensionally heterogeneous deformation characteristic is repeated periodically in one direction. In the publication, the homogenized elastic modulus is computed by identifying a unit cell (i.e., a periodic unit in the macro-structure) and assuming the unit cell to have a homogeneous material characteristic. Subsequently, the macro-structure is modeled by assuming that it has a homogenized elastic characteristic. Then, a macro-scale analysis is executed for computing the deformation of the macro-structure at a given position in the direction of the periodical arrangement. Furthermore, a local analysis is executed. In the local analysis, the obtained deformation of the macro-structure at a given position in the direction of the periodical arrangement is applied to the minute elements forming the unit cell arranged in the position, and local responses are obtained from the minute elements.
According to the publication, the structural analysis method is capable of reducing a period of time necessary for the structural computation of the macro-structure which is heterogeneous on its cross-section.
However, the structural analysis method is executed using a finite element model formed with minute elements. Accordingly, the method has a drawback in that a long period of time is required for generation and computation of a model and it cannot be thereby a useful means for time-critical initial design and early development.
On the other hand, a classical analytical model, using a spring and a dash pot, has also been conventionally used for computing the mechanical characteristic of composite materials. The computational time for this model is short and the model is efficient in this regard. However, the micro-state of a composite material cannot be taken into account in the model. Therefore, the model also has a drawback in that a computational result does not include much information and thereby the computational result is not accurate.